Characteristics of an AlN-based bulk acoustic wave resonator in the super high frequency range

摘要

We have evaluated the electrical performance of bulk acoustic wave (BAW) resonators in the range of resonance frequency from 5 to 20 GHz. The BAW resonators, consisting of a piezoelectric AlN film and top and bottom electrodes of Al/Ti films, were designed and prepared in the fundamental thickness-extensional mode. The value of effective coupling coefficient (k(eff)(2)) up to 6% and constant QF factors were achieved in these frequency ranges, which closely followed the theoretical calculation. It was found that AlN films were suitable for high frequency application because of their superior piezoelectricity even in the ultra thin region of 200 nm thickness. (C) 2008 Elsevier Ltd. All rights reserved.